LeetCode Student Attendance Record I

原题链接在这里：https://leetcode.com/problems/student-attendance-record-i/description/

题目：

You are given a string representing an attendance record for a student. The record only contains the following three characters:

1. 'A' : Absent.
2. 'L' : Late.
3. 'P' : Present.

A student could be rewarded if his attendance record doesn't contain more than one 'A' (absent) or more than two continuous 'L' (late).

You need to return whether the student could be rewarded according to his attendance record.

Example 1:

Input: "PPALLP"
Output: True 

Example 2:

Input: "PPALLL"
Output: False

题解：

计算'A'的个数和连续'L'的长度.

Time Complexity: O(s.length()). Space: O(1).

AC Java:

 class Solution {
     public boolean checkRecord(String s) {
         int countA = 0;
         int lengthL = 0;
         for(int i = 0; i<s.length(); i++){
             char c = s.charAt(i);
             if(c == 'A'){
                 countA++;
                 lengthL = 0;
             }else if(c == 'L'){
                 lengthL++;
             }else{
                 lengthL = 0;
             }

             if(countA>1 || lengthL>2){
                 return false;
             }
         }
         return true;
     }
 }